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This contribution presents a novel constitutive model for rate‐dependent response of the passive myocardium. As a first step, we performed a comparative study on dispersion‐type anisotropic hyperelastic constitutive models [1–3] and assessed performance of various density distribution functions by fitting to experiments conducted on three distinct tissues [4]. Next, we proposed an angular integration...
This article presents some historical developments in the theory of stability in mechanics from a dynamical systems point of view, focusing on mathematical methods from the earliest developments (Newton) and explaining some classical and some recent methods used, including Riemannian structures, entropy and notions of stability in dynamics.
The current research focuses on understanding the transition of pipe flow by using a triggering device. In particular, a transition rod was installed within the CoSma‐Pipe at the Brandenburg University of Technology Cottbus‐Senftenberg. The effect of the transition rod, which has a variable height perpendicular to the axis at the pipe inlet, was examined in a range of 2,500 ≤ Re ≤ 31,000 where Re...
Wind energy is an essential part of the Green Deal. The trend to increase the size of wind turbines, especially offshore, introduces additional dynamic effects at the long and flexible blades. Embedded in the CRC 1463, DFG, we are working on the fluid‐structure interaction to avoid dynamic stall and investigate flutter effects and blade breathing of ultra‐slim blades [1,2]. This requires an accurate...
Silica aerogels are highly porous ultralight materials with extremely low density and thermal conductivity. These exceptional properties of silica aerogels are often accounted to microstructure morphology, thus making them of keen research interest for analysing their structure‐property relationships. The classical approach for this involved the microstructure modelling of the silica aerogels with...
In the present work, an FE formulation using the zig‐zag hypothesis is developed for cantilever sandwich plates with viscoelastic care layer. Both viscoelastic and elastic layers of sandwich structures are considered based on the first‐order shear deformation theory to achieve higher accuracy. The FE simulation is validated by a frequency and loss factor analysis of sandwich plate. Furthermore, the...
Semi‐structural bonded joints of steel components are exposed to long‐term stresses in addition to water diffusion, temperature changes and varying external forces during operation. These hygro‐thermomechanical loadings lead to successive degradation of stiffness and strength due to damage resulting from chemical aging and fatigue processes, causing failure of the bonded joint when its service life...
Vertebroplasty, a medical procedure for treating vertebral fractures, requires medical practitioners to inject bone cement inside the vertebra using a cannula attached to a syringe. The required injection force must be small enough for the practitioner to apply it by hand while remaining stable for a controlled injection. Several factors could make the injection force unintuitive for the practitioners,...
Different numerical algorithms for the solution of a class of unsteady convection‐diffusion‐reaction (CDR) equations are presented and compared in this paper. The fully implicit in time discretizations are usually preferred because they are unconditionally stable for linear problems. However, when implicit discretization is used for nonlinear problems, iterations over the nonlinearity have to be performed...
This article presents a bioreactor study that investigates the influence of mechanical stimulation on cell migration in a cartilage replacement material. The bioreactor has been designed to carry out dynamic stimulation of cell‐seeded scaffolds, and it consists of a loading mechanism, a force‐measuring device, and a biocompatible chamber. The stimulation of the samples was carried out inside a bioreactor...
In this work, a parametric two‐dimensional computational fluid dynamics (CFD) analysis of solar chimney power plant was performed to describe the physical mechanism in order to establish realistic predictions for the operation of such plants in different location in Algeria. The developed numerical model includes a solar radiation model within the collector; an energy storage model; an air flow and...
Relaxation is a promosing technique to overcome mesh‐dependency in computational damage mechanics originating from the non‐convexity of an underlying incremental variational formulation. This technique does not require an internal length scale parameter. However, in case of damage formulations, for many years the decrease of stresses with an increase of strains, referred to as strain‐softening, could...
Soft‐Hard Active‐Passive Embedded Structures (SHAPES) are composites that respond to the environments in which they are embedded. This reaction can be a mechanical actuation, but also an intrinsic computation that yields an adaptation as a result. The actuation capabilities primarily depend on the stiffness combination of the involved materials. Stiffness includes both material parameters (depending...
Scalarization allows to solve a multi‐objective optimization problem by solving many single‐objective sub‐problems, uniquely determined by some parameters. In this work, several adaptive strategies to select such parameters are proposed in order to obtain a uniform approximation of the Pareto front. This is done by introducing a heuristic dynamics where the parameters interact through a binary repulsive...
The material properties of green wood in the shaft of vital trees differ significantly from the generally known material properties of technically processed, dried wood. Furthermore, completely different residual stresses and fracture mechanisms are present in the natural full cross‐section [1]. The properties also depend on the tree species. Our work focuses on green wood from european beech (Fagus...
We present an isogeometric finite element formulation of frictionless beam‐to‐beam contact, using a Cosserat beam formulation with unconstrained directors. The beam's cross‐sectional deformation can be efficiently represented by director vectors. For the first order beam kinematics, Poisson locking due to the inability to represent linear in‐plane strain field in the cross‐section is alleviated by...
We report on recent results on generalized surface quasi‐geostropic point vortex models. The statistical physics of these models is particularly interesting, as their mean‐field limit is a steady solution of the gSQG PDE. We present a central limit theorem‐type result for gSQG point votex models and make a comparison with results for Euler point vortex models.
Turbulent mixed convection in an air‐water system is evaluated with a novel numerical solver implementing the stochastic One‐Dimensional Turbulence (ODT) model in a turbulent air flow surrounded by a laminar cocurrent water falling film in a cylindrical geometry. The ODT model is used as a reduced order surrogate model for the effects of turbulent advection, turbulent heat flux, and turbulent mass‐flux...
Geometry conforming meshing techniques such as the finite element method (FEM) face a big challenge when dealing with complex and heterogeneous microstructures. Therefore, efficient simulation methods are needed combining accurate morphological reproducibility and computational efficiency. For such problems, the finite cell method (FCM) is a promising approach, which uses a Cartesian grid – independent...
In the fourth paradigm of science, which is data‐driven discovery, the big data collected from the first three paradigms can be analyzed to gain information of the research object. Especially in the field of material science, various big data‐driven methods are applied in the tasks, such as material detection, material analysis and material design. In the current research, we focus on how data‐driven...
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